Jakarta (VNA) - Indonesia has started cloud seeding to induce rain as the archipelago moves to head off annual forest fires blamed for blanketing swathes of Southeast Asia in toxic haze.

Over the past two weeks, cloud seeding, a technique that uses chemicals to induce rain, has been used in hotspot Riau province on Sumatra. The country plans to roll it out in other parts of the island and in Borneo.

The activity is to last throughout the dry season, which is expected to end around September.

Last year's fires were the worst since 2015 due to dry weather, with some 1.6 million hectares of land, mostly on Sumatra and Borneo islands, razed by the out-of-control blazes. 

Authorities deployed tens of thousands of personnel and water-bombing aircraft to tackle the fires, which are intentionally set to clear land for agriculture, including on palm oil and pulp plantations.

The fires sent a toxic haze across Southeast Asia that forced school closures and aggravated concerns./.